000 FXUS61 KLWX 191951 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 251 PM EST Tue Feb 19 2019 .SYNOPSIS... High pressure will build over the region through tonight. Low pressure will track from the Mississippi valley into the Great Lakes Wednesday through Wednesday night. Coastal low pressure will develop along the Mid-Atlantic Coast Wednesday night before moving off to our northeast Thursday. High pressure will return Thursday night and Friday before another low pressure impacts the area early next week. && .NEAR TERM /THROUGH WEDNESDAY/... 1040-mb high pressure system will continue to build across the northeastern US through tonight as low pressure organizes across the south central US. The primary low will eject northeastward into the Great Lakes during the day Wednesday with a secondary low developing off the Mid-Atlantic coast Wednesday evening. This setup will provide for warm overrunning aloft with cold air damming in the low levels. High clouds will be on the increase through the remainder of the day today ahead of the organizing system. High temperatures will reach into the upper 30s to mid 40s, warmest across central VA, coolest across northern MD. Temperatures will radiate this evening before cloud cover lowers and thickens. This will allow for temperatures to fall back into the 20s to around 30 degrees. Precipitation will then move towards the area late this evening, and overspread the region from southwest to northeast overnight into early Wednesday morning. A strong area of frontogenetical forcing will move across the area, and a band of moderate to potentially heavy snow is expected across the area Wednesday morning. Localized rates of 1" per hour are possible in this band. At any given location, a 4-6 hour period of snow is expected before the strong warm air advection pulls in a warm nose aloft causing snow to mix with and change over to sleet during the mid to late morning hours Wednesday for most locations, and early afternoon across northeastern Maryland. An extended period of sleet then appears likely for a good portion of the area before warming continues, changing precipitation to freezing rain and then rain. Freezing rain will persist the longest for portions of eastern WV, western MD, and northwestern VA near/west of the Blue Ridge. Snow and sleet totals from 3-6" appear most probable for locations along/west of I-95, with some areas in excess of 6" near/west of the Blue Ridge and northern MD. 2-4" of snow/sleet likely for areas south/east of I-95. This will then be followed by a light glaze of ice accrual along/east of I-95 with a tenth to two-tenths west of the I-95 corridor. Some locations may see up to three-tenths in the favored locations west of the Blue Ridge. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... Temperatures will continue to gradually warm Wednesday night with precipitation gradually changing over to plain rain. The favored locations west of the Blue Ridge may remain below freezing until the early morning hours on Thursday. Westerly flow and drying conditions will take place on Thursday with rain ending in the morning. Highs will reach the upper 40s to upper 50s. Lows Thursday night in the 30s. && .LONG TERM /FRIDAY THROUGH TUESDAY/... High pressure located over our region on Friday will begin to retreat to our north as a low pressure system to our west moves over the Great Lakes region. A warm front associated with the surface low over the Great Lakes region will move northward into our region from Carolinas. The front will start to impact our region by late Friday night and into early Saturday. Precipitation due to overruning of the warm front is forecast to affect our area late Friday. Areas over northwestern Maryland will have the potential to experience a brief period of wintry precipitation as temperatures will hover near freezing at the surface. Rain is mainly expected for most of the area as the warm front moves through on Saturday. The warm front is forecast to move to our north by Sunday morning and stall over Pennsylvania. This will place our region in the warm sector leading to rising temperatures through Sunday. Showers will be possible through Sunday afternoon as warmer and more moist air is transported into our region. Temperatures could reach up into the 60s during the day. There is some agreement that energy from the surface low over the Great Lakes may transfer along the warm front and form a secondary low along the eastern sea board near New Jersey and New York. This could act as additional focus for more showers to form in our region. The cold front associated with the low pressure system moving to our northwest will move through our region sometime Sunday afternoon bringing more widespread rain. Behind the frontal passage Sunday evening, winds will become westerly with upslope induced showers possible along the the Allegheny Highlands and the Appalachian spine. High pressure is forecast to build into our region from the midwest through Tuesday morning. Temperatures will trend back downward behind the frontal passage. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... Snow expected late tonight into Wednesday morning, mixing with and changing to sleet/freezing rain by late morning Wednesday and eventually to plain rain Wednesday evening. Expect IFR or lower ceilings/visibilities, with the lowest visibilities in snow Wednesday morning, and the lowest ceilings Wednesday evening and night. Conditions improve Thursday. On Friday, skies clear some with light winds out of the north. VFR conditions are expected. Saturday, showers will move into the region from the south. Skies will become overcast with winds becoming southerly. SubVFR conditions are possible. && .MARINE... Winds have fallen below SCA criteria this afternoon and will remain below tonight. Some increase in easterly flow is expected on Wednesday and winds may approach SCA criteria, but have left below for now as mixing will be limited due to snow and mixed precipitation. Sub-SCA winds then expected Thursday and Thursday night. For Friday, winds will remain light out of the north, turning southerly later Saturday. No Small Craft Advisories expected at this time. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Winter Storm Warning from 1 AM to 7 PM EST Wednesday for DCZ001. MD...Winter Storm Warning from 1 AM Wednesday to 1 AM EST Thursday for MDZ003-004-501-502. Winter Storm Warning from 1 AM to 7 PM EST Wednesday for MDZ013-503>506. Winter Storm Warning from 4 AM to 7 PM EST Wednesday for MDZ005-006-011-014-507-508. Winter Weather Advisory from 1 AM to 4 PM EST Wednesday for MDZ016>018. VA...Winter Storm Warning from 10 PM this evening to 10 PM EST Wednesday for VAZ025-026-036>038-503-504-507-508. Winter Storm Warning from 1 AM Wednesday to 1 AM EST Thursday for VAZ027>031-040-501-505. Winter Storm Warning from 1 AM to 7 PM EST Wednesday for VAZ039-050>054-502-506. Winter Weather Advisory from 1 AM to 4 PM EST Wednesday for VAZ055>057. WV...Winter Storm Warning from 10 PM this evening to 10 PM EST Wednesday for WVZ505-506. Winter Storm Warning from 1 AM Wednesday to 1 AM EST Thursday for WVZ050>053-055-501>504. MARINE...Small Craft Advisory until 3 PM EST this afternoon for ANZ533- 534-537-541-543. && $$ SYNOPSIS...MM NEAR TERM...MM SHORT TERM...MM LONG TERM...JMG AVIATION...MM/JMG MARINE...MM/JMG